In short: Coco coir (also called coco peat or coir pith) is the spongy material made from the husk of coconuts. It's a peat-free growing medium widely used by UK gardeners and commercial growers. Sold as a 5 kg compressed brick that expands to roughly 75 litres when hydrated. Buffered coir comes pre-treated for stable nutrient uptake.
What Is Coco Coir? The Complete Expert Guide for UK Growers
Coco Coir — also known as coir pith or coco coir — is a natural, peat-free growing medium made from the fibrous husk of coconut shells. It is the by-product of the coconut fibre industry and has become one of the most popular growing media for UK gardeners, horticulturalists, and commercial growers looking for a sustainable alternative to traditional peat moss.
How Is Coco Coir Made?
Coconut husks are soaked in water to loosen the fibres — a process called retting. The long fibres are extracted for use in ropes, mats, and brushes. The fine spongy material left behind is coco coir. It is then dried, compressed into bricks or blocks, and shipped worldwide.
When you add water to a coco coir brick, it expands dramatically — a 5 kg brick from Blue Apple Garden expands to approximately 75 litres of ready-to-use growing medium.
What Are the Properties of Coco Coir?
- pH: Naturally between 5.5 and 6.8 — ideal for most plants
- Water retention: Holds up to 10 times its own weight in water
- Aeration: High air porosity (typically 22–30%) prevents root suffocation
- EC (Electrical Conductivity): Ultra-low EC in buffered coco coir (0.1–0.5 mS/cm) — minimal salt stress on plants
- Texture: Fine, crumbly, and lightweight
- Longevity: Can be reused for multiple growing cycles if properly flushed and re-buffered
What Is Buffered Coco Coir?
Raw coco coir contains naturally occurring potassium and sodium salts that can compete with calcium and magnesium uptake in plants. Buffered coco coir has been pre-treated with a calcium-magnesium solution to flush out these salts and stabilise the cation exchange sites before it reaches your garden.
At Blue Apple Garden, all our coco coir bricks are fully buffered, meaning they are ready to use straight from the brick — no pre-flushing required.
Learn more: Buffered vs Unbuffered Coco Coir — What's the Difference?
What Is Coco Coir Used For?
- Seed starting: Excellent germination medium — fine texture supports delicate roots
- Potted plants and houseplants: Lightweight, moisture-retaining, and re-wettable
- Raised beds and allotments: Mixed with compost or topsoil to improve drainage and water retention
- Hydroponics: Widely used in NFT (Nutrient Film Technique), drip, and hand-watered systems
- Propagation: Root cuttings more reliably than in pure compost
- Commercial horticulture: Tomatoes, cucumbers, peppers, and herbs in greenhouse production
How Does Coco Coir Compare to Soil and Peat Moss?
| Property | Coco Coir | Traditional Soil | Peat Moss |
|---|---|---|---|
| Sustainability | ✅ Renewable by-product | ⚠️ Resource-limited | ❌ Non-renewable, CO₂-releasing |
| pH | 5.5–6.5 (stable) | Variable (4.5–8.0) | 3.5–4.5 (acidic) |
| Water retention | Very high | Variable | Very high |
| Aeration | Excellent | Variable | Poor when compacted |
| Reusability | Yes (2–3 cycles) | Yes | Limited |
| UK retail status | ✅ Standard at major UK retailers | ✅ Standard at major UK retailers | ❌ Phased out at major UK retailers |
Read: Coco Coir vs Peat Moss — Which Is Better?
Is Coco Coir Good for All Plants?
Coco Coir suits the vast majority of UK garden plants. It is particularly effective for:
- Tomatoes, peppers, and cucumbers (greenhouse or polytunnel)
- Houseplants — ferns, monsteras, pothos, philodendrons
- Herbs — basil, coriander, mint, chives
- Orchids (mixed with perlite)
- Raised bed vegetables
- Seedlings and cuttings
For acid-loving plants such as blueberries, heathers, and azaleas, the neutral-to-slightly-acidic pH of coco coir may need adjustment with sulphur chips. Pure coco coir is generally too free-draining for cacti and succulents without amendment.
Where Can I Buy Coco Coir in the UK?
Blue Apple Garden supplies premium buffered coco coir bricks with free UK delivery. Our 5 kg bricks expand to 75 litres, and our 15 kg packs (3 × 5 kg bricks) expand to 225 litres — ideal for raised beds, greenhouse runs, and large containers.
Shop Buffered Coco Coir Bricks →
Frequently Asked Questions
Is coco coir the same as coco coir?
Broadly, yes. Coco coir is the collective term for all coconut husk fibre products. Coco Coir (or coir pith) refers specifically to the fine, spongy material — as distinct from long-fibre coir used in brushes and ropes.
Does coco coir contain nutrients?
Coco Coir contains trace amounts of potassium and phosphorus but is not a significant nutrient source. It is used as a growing medium structure, not a fertiliser. You will need to feed plants separately.
How long does coco coir last?
A single batch of coco coir typically lasts 2–3 growing seasons before it degrades and loses its structure. Between cycles, flush with fresh water and check EC levels before reuse.
Can I add coco coir to my existing compost or soil?
Yes. A 30–50% coco coir blend with compost or topsoil improves aeration and water retention significantly, especially in clay-heavy or compacted soils.